Main Characteristics of Monotremes

There are only five species of monotremes: the platypus and four species of echidnas (one short-beaked echidna and three long-beaked echidnas).
Monotremes are the only mammals that don't give birth to live young. They lay eggs.
Monotremes means „single opening“ in Greek and refers to their unique anatomy. They have a single exit for both reproductive and excretory systems. It is called the cloaca. This is different from all other mammals that have separate openings.
Monotremes are carnivores.
Monotremes possess an electro-sense, allowing them to detect the electrical signals emitted by other living creatures using their snout, bill or beak.
Monotremes have a noticeably low body temperature. It is 86-89 degrees Fahrenheit (30-32 degrees Celsius).
Monotremes live in Australia, Tasmania and New Guinea.

Monotreme Family Tree